Thu, 10 Apr 2008

Dave has been experimenting with xorg configuration lately -- trying
to figure out why the latest Xorg no longer supports 1600x1200 on
his monitor. (I've looked for bug reports and found gazillions of
them, all blaming it on the video card but involving three different
makes of video card, so color me skeptical.)

Anyway, part of this has involved taking out parts of his
/etc/X11/xorg.conf file to see which parts might be causing the
problem, and he's found something interesting.

What do you suppose is the minimal useful xorg.conf file?
You might suppose, oh, screen and monitor sections, an input section
for the keyboard and another one for a generic mouse, and that might
be all you need ... right?

Okay, try it. Let's start with a really minimal file -- nothing --
and gradually add sections. To try it, make a backup of your current
xorg.conf, then zero out the file:

cd /etc/X11
mv xorg.conf xorg.conf.sav
cp /dev/null xorg.conf

Now exit X if you hadn't already, and start it up again (or
let gdm do it for you).
Be prepared to do repairs from the console in case X doesn't start up: e.g.
sudo cp /etc/X11/xorg.conf.bak /etc/X11/xorg.conf

What happened?

In my case, on the laptop running Hardy beta, X starts right up and
looks just the same as it did before.

xorg.conf -- who needs it?

A specious question, of course, which has a perfectly good answer:
anyone who needs a resolution other than whatever xorg picks as the default;
anyone with additional hardware, like a wacom tablet;
anyone who wants customizations like XkbOptions = ctrl:nocaps.
There are lots of reasons to have an xorg.conf. But it's fun to
know that at least on some machines, it's possible to run without one.

Update: turns out this is part of Ubuntu's new
BulletProof X
feature. It doesn't work on other distros or older versions.
Thanks to James D for the tip.